<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>CSS盒子模型</title>

    <style>
      .demo1 {
        background-color: aqua;
        display: inline-block;
        border: 5px solid yellowgreen;

        padding: 20px;
      }

      .demo2 {
        background-color: yellowgreen;
        width: 200px;
        height: 100px;
        border-style: solid dashed dotted double;
        border-width: 10px 5px;
        border-color: tomato;

        margin: 10px;
      }
      .demo3 {
        background-color: yellowgreen;
        width: 200px;
        height: 100px;
        border-left: 10px solid tomato;
      }
    </style>
  </head>
  <body>
    <div class="demo1">这是一个边框示例</div>
    <div class="demo2">这是一个边框示例</div>
    <div class="demo3">这是一个边框示例</div>
  </body>
</html>
